High-precision wideband amplifiers have broad application in modern electronic equipment, particularly measurement instruments. A trend in designing high-precision differential amplifiers is to incorporate mechanisms within the circuit to significantly reduce or cancel non-linearity and thermal distortion error which is inherent in the physical properties of semiconductor pn junctions. One such amplifier design which provides vastly improved performance is the cascode feed-forward amplifier taught by Quinn in U.S. Pat. No. 4,146,844, which is assigned to assignee of the present invention. The Quinn feed-forward amplifier employs a correction channel which senses pn junction distortion of a main channel and injects an error-correction signal into a pair of output nodes. The main channel, however, is a cascode amplifier having at least four transistors in the signal-current path, and as a consequence of the sub-unity value of alpha, the transconductance of the amplifier contains a slight residual error which results in a non-linear and thermally-dependent gain reduction.